I know it's not ideal but I can't see a better way of making the plasma cutter work, when D type is the recommended fuse. I've checked the welder manual too now and it recommends a D45 or D63, no wonder it occasionally tripped the B32. I never use it on more than 3/4 power so the D32 should solve that issue too.Sounds fine then.
For overload protection then yes.
For fault protection it would also depend on the sub-board Zs which in turn depends on your supply Ze and the sub-main feeding that CU. Of course you can disconnect using the RCD to avoid the demanding final Zs value, but MCB are fare more reliable so I always feel a little uneasy going down that route.
Essentially your NYYJ R1+R2 would be added to your sub-main R1+R2 and your supply Ze and the total final circuit Zs has to be 0.28 ohm or less to meet 0.4s ADS.
Would you actually test your RCD regularly using the test button?
I do agree with what you are saying, but if my supply Ze is high there isn't much I can do about it is there? I will get it tested but I don't think there will be a resistance problem over 30ft of 16mm then 10ft of 6mm surely? So if the total Zs is high it will be the supply so I'll be stuck using the RCD anyway
Last edited: